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When your project demands a spring that fits where nothing else will, finding a reliable small-diameter compression spring becomes a real challenge. Hobbyists, model makers, electronics repair technicians, and precision instrument builders all face the same frustration: standard springs are simply too large. These compression springs with a 0.3mm wire diameter are engineered for exactly those demanding, space-constrained applications.
Each spring is formed from carbon steel wire with a wire diameter of 0.3mm and an outer diameter ranging from 2mm to 6mm (approximately 0.08 in to 0.24 in). Free lengths span 5mm to 50mm (approximately 0.20 in to 1.97 in), with a consistent close-coiled cylindrical body and flat, ground ends for stable seating. The finish is a natural bright steel.
Typical use cases include pen and mechanical pencil mechanisms requiring a small return spring, miniature electronic switch assemblies needing a light-load compression spring, scale model suspension and linkage systems, precision instrument latches and detent mechanisms, and DIY repair of small appliances where an original spring has fatigued or broken.
Ultra-fine wire gauge enables use in miniature assemblies where standard springs cannot fit, maintaining consistent coil geometry throughout the spring body.
Six outer diameter options (2mm, 2.5mm, 3mm, 4mm, 5mm, 6mm) let you match the spring precisely to your bore or seat diameter without modification.
Ten length options from 5mm to 50mm per OD group give you control over travel distance and compressed height to suit your design envelope.
Formed from carbon steel wire, these springs deliver reliable elastic return force and resist permanent set under normal operating loads within their rated deflection range.
Available in packs of 5, 10, 50, and 100 pieces so you can order a sample set for prototyping or stock up for production runs without overpaying.
Uniform coil pitch and flat (ground) end treatment ensure square seating against spring seats, reducing side-load and improving load linearity in your assembly.
| Spring Type | Compression Spring |
|---|---|
| Wire Diameter | 0.3 mm (0.012 in) |
| Outer Diameter (OD) | 2 mm / 2.5 mm / 3 mm / 4 mm / 5 mm / 6 mm — see variant options |
| Free Length | 5 mm – 50 mm — see variant options |
| Material | Carbon Steel |
| Surface Finish | Bright (natural steel) |
| End Type | Closed & Ground (flat ends) |
| Coil Direction | Right-hand |
| Spring Rate | See variant options |
| Pack Quantity | 5 / 10 / 50 / 100 pcs — see variant options |
| Operating Temperature | Suitable for standard ambient conditions; contact us to confirm for elevated-temperature use |
Measure the bore or spring seat in your assembly. The spring's outer diameter should be slightly smaller than the bore so it can compress freely without binding. For a shaft-guided spring, the inner diameter (OD minus twice the wire diameter) should clear the shaft with a small gap. Use the variant selector above to choose from 2mm, 2.5mm, 3mm, 4mm, 5mm, or 6mm OD.
The free length should be long enough that the spring is still under slight compression when installed (pre-load), and short enough that it does not reach solid height (coil bind) at maximum deflection. Measure your available cavity depth and your required travel, then choose a free length from 5mm to 50mm that gives you adequate working stroke.
With a 0.3mm wire diameter, these are light-duty springs suited for low-force applications such as switch returns, pen mechanisms, model linkages, and instrument detents. They are not intended for heavy mechanical loads. If you need the specific spring rate (N/mm) for your design calculation, please contact us with your OD and length selection and we will provide the data.
These springs are made from carbon steel with a bright finish and do not have a corrosion-resistant coating. They are suitable for dry indoor environments. For applications exposed to moisture, humidity, or mild chemicals, consider applying a light oil or protective coating after installation, or contact us to ask about stainless steel alternatives.
Yes. The small outer diameters (2mm–6mm) and fine wire gauge make these springs well-suited for use in keyboard switches, battery contacts, push-button mechanisms, and similar PCB-mounted or chassis-mounted applications where a light return force is needed. Ensure the spring does not create an unintended electrical short path in your circuit layout.
All packs contain identical springs — the only difference is quantity. The 10-piece pack is ideal for prototyping or single-unit repairs. The 50-piece and 100-piece packs offer a lower per-unit cost and are suited for small production runs, repair kits, or stocking a workshop with a range of sizes. Select your preferred quantity in the "Length(mm) & Qty (pcs)" variant option above.
Solid height is approximately equal to the total number of coils multiplied by the wire diameter (0.3mm per coil). Estimate the number of coils as the free length divided by the coil pitch. Ensure your assembly's minimum compressed length is greater than the calculated solid height to avoid coil bind, which can damage the spring or the surrounding components.
